What is EVA material?
EVA is made from ethylene-vinyl acetate copolymer (also known as ethylene-vinyl acetate copolymer) by copolymerization of ethylene (E) and vinyl acetate (VA). The English name is: Ethylene Vinyl Acetate, abbreviated as EVA, E/VAC. . The polymerization method uses high pressure bulk polymerization (for plastics), solution polymerization (PVC processing aid), emulsion polymerization (binder), and suspension polymerization. The ethylene acetate (VA) content of more than 30% is emulsion polymerization, and the low vinyl acetate content is polymerized by high pressure.
EVA features and uses
EVA pellets can be processed into various types of EVA sheets, and then the sheets are processed through various processes. For example, the stamping type can be used as a packaging liner, and the hot pressing can be made into a sole. Shenzhen Yidebao is so foamed and then supplied to other customers.
Biodegradable: Does not cause harm to the environment when discarded or extinguished. EVA materials can be used in the electronics, hardware and toy industries.
Similar to the price of PVC: EVA is more expensive than toxic PVC, but relatively cheaper than phthalate-free PVC.
Lighter weight: EVA has a density ranging from 0.91 to 0.93, while PVC has a density of 1.32.
No odor: EVA does not contain ammonia or other organic flavors.
Contains no heavy metals: Complies with international toy regulations (EN-71Part3 and ASTM-F963).
Phthalate-free: suitable for children's toys and does not pose a risk of plasticizer release.
High transparency, softness and toughness: a wide range of applications.
Super low temperature resistance (-70C): Suitable for icing environment.
Resistant to water, salt and other substances: can be determined in large applications.
High heat-adhesive: It can be firmly applied to nylon, polyester, canvas and other fabrics.
Low fit temperature: speeds up consumption.
Screen printing and offset printing: can be used for more versatile products (but EVA inks are required).
EVA foam material formula
EVA foaming formula is composed of the following raw materials: main material, filler, foaming agent, bridging agent, foaming accelerator, smoothing agent.
Obviously, the main ingredient is EVA. Of course, in order to improve the physical properties of the product, it is also possible to properly add some other materials, such as rubber, POE, etc., and even add a little TPR to enhance certain physical properties. EVA, the main indicator is the VA content, and its upper and lower resolutions are directly related to all the performance of EVA foam products. of course. Some can only be foamed with PE. The main material used in detail depends on the request of the product. -TSiawzV/Q:r
Filler, currently used calcium carbonate or talcum powder. Its use and cost reduction, increase product rigidity, etc., can also play a role in heat conduction. Generally, the particle size is used as the quality index (of course, the water content is also on the one hand), for example, 120 mesh, 400 mesh, and the like. On the standard rope, the finer the better, of course, the price will be higher. The maximum dosage is 40Phr (the percentage of the main material) in the formulation I have seen. The general use of AC series foaming agent, such as AC-3000H, AC series foaming agent is a high temperature foaming agent. The synthesis temperature is over 220 degrees. There are also low-temperature foaming agents, such as AD-300, the synthesis temperature is 140 degrees, and there is a medium temperature foaming agent. Because the price difference is not large, and the high-temperature foaming agent will be relatively stable, so many old EVAs are now using high-temperature, and also have a combination. The amount of AC is based on the detailed magnification. The bridging agent, which is the most used today, is DCP. It used to be TAIC, PL400, etc. The half-life of DCP is 1 minute at 180 degrees and 10 minutes at 130 degrees. Therefore, when ordinary materials are used, the temperature should be controlled below 120 degrees. Some products have a request for breath, and can use another bridging agent BIPB, which is commonly used in conjunction with TAIC. The amount of DCP used in the foaming of the flat plate and the small foaming in the mold is generally 0.5-0.6 Phr, and the ordinary body foam is 0.8-1.0 Phr. Of course, there are also appropriate additions and subtractions, and there are different usages. There are two types of foaming accelerators, zinc oxide powder and zinc stearate. In the past, we used these two combinations, and now only use zinc oxide. A single one can also achieve the effect, and the stability of the product may be better. Zinc oxide can reduce the synthesis temperature of AC to about 160 degrees, which is convenient for consumption. We have a consensus that the amount of ordinary zinc oxide does not exceed 0.2Phr, and the shrinkage of excessive products will be relatively large. Of course, too little foaming speed is too slow, so it is best not to be less than 1.0 hr / smoothing agent, common stearic acid. In fact, it doesn't make much difference. It is to let the machine not stick to the material. It is not good to use more, because it can reduce the friction between the points, so that most of the physical properties are reduced. Referral 0.5Phr. Later, we will introduce the addition of excipients in EVA foam.
Addition of excipients in EVA material foaming formula
The excipients that can be added to the EVA formula are very mixed. Just talk about a few major categories.
1 trim. The trimmings are some of the excess tails and side bars after the product is made. They are all foamed. This kind of thing is a cost killer, it can greatly reduce the cost of consumption, of course, it will also have the impact on physical properties. This kind of thing is all about EVA, I will not go into details.
2 antistatic agents Some products, request for antistatic function, and EVA foam products themselves with a strong static, so it is necessary to add some antistatic agents in the formula. The antistatic agents used in ordinary EVA are all mixtures. The detailed composition of MS is very complicated. I can't say it at any time, and the dosage is 3%-5%.
3 Flame Retardant EVA foam products used as certain packaging materials may require flame retardancy. It is possible to properly add a flame retardant to the formulation to achieve a flame retardant effect. The commonly used flame retardant Mg(OH)2, Al(OH)3 in plastics also has certain effects on EVA foaming products, but the dosage is relatively large, we use 12%-20%, but the products with high flame retardant requirements They are not very useful. A product in Japan has a very good flame retardant effect, but it does not comply with the ROHS directive. Therefore, in a word, I am not very good at the high demand for flame retardant. 4 fast-cooking agent EVA foaming process is time-consuming. If you want to improve daily output and reduce product energy consumption, you can properly add fast-cooking agent to shorten the time required for foaming. The most common quick-curing agent on the market today is TAIC, which is supposed to be a bridging aid. Adding the right amount of TAIC can indeed shorten the time, but as it participates, the size of the product will be reduced accordingly, and the time reduction effect is not very satisfactory. I don't know Fujian. Today, there are several kinds of fast-cooking agents in the center of Guangdong. The amount of addition is small, and the effect of shrinking time is quite impressive. (Speak quietly, this quick cooker, I leaked it in.) l5 colorant foaming products are generally colored, so it is necessary to add coloring agents to the formula to color. EVA foam products can be used with toner, color glue, and of course, it is better to use masterbatch. MS products can't use computer color matching, it may be because the color change before and after foaming is too big, and the computer is not dead.
Development trend of EVA foam materials
The consumption and application of China's EVA foam materials started late, but due to the excellent processing performance and common application of the products, the demand growth has been very fast in recent years, and the market is currently in the growth period. Although the downstream export demand has weakened under the impact of the global financial crisis, the compound growth rate of the market from 2006 to 2010 still exceeds 9%. In 2010, the market scope exceeded 18 billion yuan.
The rapid growth of the market has absorbed many manufacturers into the industry. In 2010, more than 3,000 companies in the Chinese market have the ability to consume EVA foam materials. Most of the consumers of EVA foam materials are small enterprises with annual sales of less than 10 million yuan. The number of large-scale consumers is small, and its annual sales are more than 30 million yuan, and the high is up to 100 million yuan. The sales of the top 5 EVA foam materials in the market are close to 2 billion yuan, accounting for only 10% of the market share, and the concentration is not high.
Benefiting from the stable development of China's manufacturing industry, the increase in requests and profits brought by the promotion of downstream industries, and the wider application areas will be developed and other favorable factors, it is estimated that China's EVA foam materials market will maintain rapid growth. From the beginning of 2010, the compound annual growth rate will exceed 10%, and by 2015 the market will reach 30 billion yuan.
Raw materials mainly depend on imports
The main raw material for EVA foam materials is EVA. At present, the demand for EVA foam materials for EVA accounts for more than 60% of the total domestic EVA consumption. As China's apparent consumption of EVA foam materials has increased year by year, the demand for EVA has been boosted. In the past few years, the average annual growth of China's EVA demand has exceeded 7%. On the other hand, the dependence of market supply on imports is relatively high. In 2010, global EVA demand exceeded 3 million tons, domestic EVA consumption reached 700,000 tons, and output was only 270,000 tons, and self-sufficiency rate was 40%.
Due to tight market supply, rising raw materials, energy and transportation costs, EVA import prices rose from 2006 to 2008, rising from 10,800 yuan (ton price, the same below) to 13,600 yuan. In 2009, due to the fall in international crude oil prices, the cost of EVA consumption fell. On the other hand, the financial crisis has also led to a reduction in demand for EVA on a global scale. These two factors have caused the import price of EVA to fall to 10,200 yuan in 2009. In 2010, with the gradual recovery of the macro economy, the downstream demand of EVA gradually increased, while the international crude oil price rose, the supply of EVA continued to panic, causing the EVA price to rise rapidly to 13,500 yuan.
The price of EVA foam materials has also been shaken with the price of EVA. From 2006 to 2008, the price of EVA foam materials rose from 3,150 yuan to 3,600 yuan / cubic meter. By 2009, along with the fall in EVA prices, the price of EVA foam materials also dropped to 3,200 yuan / cubic meter. In 2010, due to the rapid growth of downstream demand and the sharp rise in EVA raw materials, the price of EVA foam materials rebounded back to 3,500 yuan / cubic meter.
Strong downstream demand growth
The main business of EVA foam materials, namely footwear, luggage, toy industry, sporting goods industry, building materials industry, is a traditional strong industry in China's manufacturing industry. In 2010, the output value of the industry exceeded or nearly 100 billion yuan, including building materials. The industrial output value has reached more than one trillion yuan. Driven by further improvement in domestic demand and export markets, it is estimated that these industries will continue to grow by more than 10% in the next three years.
The footwear market and the luggage industry market are the most important downstream markets for EVA foam materials. In 2010, about 70% of EVA foam materials in the Chinese market were consumed. In the downstream market of EVA foam materials such as toy industry, sporting goods industry and building materials industry, about 25% of EVA foam materials in the Chinese market were consumed in 2010. Emerging areas, such as automotive interiors and electronic components, have cost about 5% of EVA foam in the Chinese market.
Continue to improve in the future
The high-growth market will absorb more companies, but technical barriers, especially the request for recycling performance of EVA foam materials, as well as the scope and financial barriers, will limit the entry of companies with small scope and lack of resources. Although there is no product specification for the EVA foam material industry, the request for various products, especially the increasingly strict export specifications, also constitutes a strong constraint on EVA foam materials. Therefore, consumers who meet the various specifications of the downstream will be in a more favorable position in the competition.
From the upstream, with the expansion of demand for EVA foam materials in the Chinese market, EVA imports will further increase in the future. At the same time, as the technology of domestic consumer companies breaks down, the dependence on imports will gradually decrease. Driven by downstream demand, the market scope of China's EVA foam materials will continue to increase. At the same time, it is estimated that large EVA foam material consumers will further occupy the market, and the industry will complete local industry integration through mergers and acquisitions. From the downstream, on the one hand, the existing demand for the industry will continue to be strong, and with the promotion of the next industry, the request for the quality and characteristics of EVA foam materials will also increase, but also bring higher profits. On the other hand, more emerging applications will be developed.
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